KOSEN 한인과학기술자네트워크

Signal transduction is the process by which a cell recognizes changes in its environment and transforms that signal into modifications in cellular activity and gene expression. These processes are often initiated through receptor ligation or stress, and may involve a cascading series of intracellular biochemical events that are amplified and integrated to achieve the desired cellular response. For instance, activated kinases can catalyze the transfer of a phosphate group to serine, threonine, or tyrosine residues on target proteins and regulate protein activity, localization, and protein-protein interactions. Activities modified by phosphorylation can in turn be terminated by the phosphatases. Signal transduction cascades may also involve non-enzymatic second messengers including cyclic nucleotides (cAMP and cGMP), Ca2+, and lipids. These intracellular signaling events regulate virtually all cellular activities. Therefore, it is critical to have quality tools that make it easy to study factors involved in signal transduction. Transcriptional regulation is fundamental to all biological systems, from the simplest virus to complex multicellular organisms. In eukaryotes, regulation begins at the level of transcription initiation, which is controlled by a group of proteins called transcription factors (TFs). Through different combinations of regulatory mechanisms, eukaryotes are able to elicit myriad gene expression patterns. In effect, TFs act as sensors, adjusting their activities according to changes in cellular conditions. For this reason, TFs can be used as markers for monitoring these changes and linking them to gene expression.